How to Kill an Asteroid: The Real Science of Planetary Defense

by Robin George Andrews

A gripping account of the “city-killer” asteroids that could threaten Earth and the race to build a planetary defense system.

There are approximately 25,000 “city-killer” asteroids in near-Earth orbit—and most are yet to be found. Small enough to evade detection, they are capable of large-scale destruction, and represent our greatest cosmic threat. But in September 2022, against all odds, NASA’s Double Asteroid Redirection Test (DART) mission deliberately crashed a spacecraft into a carefully selected city-killer, altering the asteroid’s orbit and proving that we stand a chance against them.

In How to Kill an Asteroid, award-winning science journalist Robin George Andrews—who was at DART mission control when it happened—reveals the development of the technology that made it possible, from spotting elusive asteroids and comets to figuring out their geologic defenses and orchestrating a deflection campaign. In a propulsive narrative that reads like a sci-fi thriller, Andrews tells the story of the planetary defense movement, and introduces the international team of scientists and engineers now working to protect Earth.

Genres: Science, Nonfiction, Space, Astronomy, History, Audiobook

336 pages, Hardcover

Published October 1, 2024

About the author

Robin is perpetually curious and often ridiculous. He’s a doctor of experimental volcanology (blew stuff up for science) a full-time, freelance, award-winning science journalist (rearranges letters for money), a part-time award-winning photographer (takes photographs that aren’t awful), a scientific consultant (tells people how to do science right), an occasional lecturer (rearranges letters and says them aloud for money), a public speaker (rearranges letters and says them aloud, sometimes for free), and a frequent explain-how-volcanoes-work TV guest (gesticulates wildly on live television). His work has appeared in The New York Times, The Atlantic, National Geographic, Scientific American, Quanta Magazine, Vox, Nature, Earther, Gizmodo, Forbes, The Verge, Atlas Obscura, New Scientist, Supercluster, Discover Magazine, WIRED, CNN, the Guardian, the Observer, The Times, The Daily Beast, and elsewhere.

(He’s enjoyed all his assignments, but he’s especially pleased three of his stories made the front page of The New York Times – with two of these and one other making the cover of the Science Times section – and another tale was made Scientific American’s cover story. Although all that might pale in comparison to his National Geographic story on an unsolved “murder” mystery—because that one went viral and got turned into TikToks, which was adorable. Oh, and one of his pieces – this one – was listed as a notable essay in the 2021 edition of the Best American Science and Nature Writing, which was lovely. He’s also appeared multiple times on Science Shortform’s best science journalism roundups, both as Honorable Mentions and Top Picks.)

You can also sometimes see his goofy face appear on TV, including on BBC News, Sky News, Al Jazeera, and Good Morning America. If faces aren’t your thing, you can hear his exceedingly British accent on the Guardian’s podcasts.

He’s also the author of a popular science book published by W.W. Norton & Company — SUPER VOLCANOES: WHAT THEY REVEAL ABOUT EARTH AND THE WORLDS BEYOND — and it’s about (you guessed it) volcanoes. Many see volcanoes as little more than unpredictable magmatic killers. But for the most part, they are fantastical masterworks of molten rock capable of near-magical acts. And as they put on a pyrotechnical performance, they reveal secrets about the planets to which they belong. In other words, volcanoes aren’t frightening; they’re breathtaking, bizarre, and bonkers. They are citadels built by frozen lava that provide revelation after revelation about the Stygian depths and the strange surfaces of worlds near and far, including the only home we’ve ever known.

He is also the 2022 recipient of the European Geosciences Union's Angela Croome Award for continued, excellent and successful reporting of Earth, space & planetary science topics—something he received the day after his first book was published in the US, making those 48 hours pretty damn exciting.

Find him here, sometimes on this, and elsewhere. If you happen to be in London, he'd much prefer to meet at the Mayor of Scaredy Cat Town. Yes, he's always available to cameo in Star Wars and Doctor Who.

Reviews

[Rebecca Renner · Rating 5 out of 5]

I had the honor of blurbing this book. Here's what I said: "If you ever lie awake at night dreading Earth's impending doom from an asteroid impact, you should read Robin George Andrews's How to Kill an Asteroid. In this highly readable and engaging book, you'll learn about the science of planetary defense and all the scientists preparing to save Earth—if that time ever comes. Exciting and surprisingly funny, How to Kill an Asteroid is a must-read for space enthusiasts and anyone who enjoys good narrative science journalism."

[CatReader · Rating 4 out of 5]

3.5 stars rounded up. Robin George Andrews is a British PhD volcanologist and science writer. In 2024's How to Kill an Asteroid (which has possibly the cheesiest cover art I've seen in a nonfiction science book in a long time), Andrews explores other scientists' efforts in a science-fiction/'90s-Hollywood-blockbuster-turned-reality aspect of planetary defense: monitoring and destroying asteroids that could destroy our planet. He writes extensively about NASA's Double Asteroid Redirection Test (DART), where a spacecraft purposely impacted a moonlet asteroid called Dimorphous in 2022. He also writes about the OSIRIS-REx mission led by Dante Lauretta (which Lauretta wrote about in a full-length book, The Asteroid Hunter: A Scientist’s Journey to the Dawn of our Solar System, and I reviewed in detail here). He also talks about military and international asteroid impact simulation events -- for anyone with existential angst on this topic, I'd recommend browsing the NASA Jet Propulsion Laboratory's website monitoring near earth objects for reassurance.

I appreciated Andrews' enthusiasm and geekiness (I say that as a compliment) for this topic, which sounds like it dovetailed nicely with Andrews' geology background. Most books of this sort that I tend to recommend are written by the scientists who worked on these missions themselves (see Lauretta's book above, as well as books like Alan Stern's Chasing New Horizons: Inside the Epic First Mission to Pluto), though given Andrews' background I don't perceive his outsider status as a negative here. I did find this book to be a bit repetitive and too long to hold my interest throughout, though this is likely more to do with me and the books I've already read on this topic than on Andrews.

My statistics:
Book 65 for 2025
Book 1991 cumulatively

[Peter Tillman]

Author's preview: https://robingeorgeandrews.com/how-to...

[Wayne · Rating 4 out of 5]

The authors writing style is easy to understand. It is thoroughly supported by a detailed bibliography which reflects in depth organization and knowledge on the subject matter. Although entertaining, this work is also an excellent reference for further study.

[Ramello S · Rating 5 out of 5]

It took quite some time to finish this book, but every time I picked it up, I enjoyed every second. Written like a novel, this book gives you exactly what it said it would, the real science of planetary defense. It's the perfect mix of non-fiction, science, and storytelling, with a splash of comedy here and there. Quite honestly, it's given me hope for the survival of this blue marble floating through space, no matter how crazy it gets.

[Sam Talkington · Rating 4 out of 5]

Love anything space.

The author reports great things going on at The University of Washington Astronomy department (I took astronomy 101 there).

Book primarily focuses on city killer asteroids and the DART mission.

Learned a lot. Great book.

[Jackie]

I read this book in 4 hours from midnight. I had intended to read the first page or two as I was excited to have purchased it. The book was so compelling I literally could not stop reading it. A wonderful story that unfolds as you read. To top it, all its a story of potential catastrophe for us, but has a feel good ending. So good.

[Charlotte · Rating 4 out of 5]

What a great read! Fun and so informational!

[Jessica · Rating 5 out of 5]

The cover art and title caused me to think this book might be silly. I'm glad I eventually took a chance and purchased it. This was as fun as the cover indicated but at the same time, it is most definitely a serious read.

My only complaint is that the chapter titles don't tell me what I'm about to read so I made up my own chapter titles so I can find the parts I like more easily.

Chapter 1: Anatomy of a comet/asteroid and a brief history of Shoemaker-Levy 9, Chelyabinsk and Tunguska.

Chapter 2: The DART Mission is funded and assembled.

Chapter 3: The nuclear option for deflecting an asteroid. A nuke is the most effective tool we CURRENTLY possess. But it makes people nervous and with good reason.

Chapter 4: How Astronomers find asteroids and monitor their orbits. JPL's Center for Near Earth Object Studies uses algorithms to keep track of asteroids near us, the one it knows about at least...

Chapter 5: Pre-DART Projects: Deep Impact, Rosetta (comet research), Hayabusa 2 (retrieved material from a rubble pile asteroid), OSIRIS-REx (landed a craft on asteroid Bennu and retrieved a sample).

Chapter 6: Impact Craters on Earth.

Chapter 7: Planetary Defense War Games.

Chapter 8: NEO Surveyor. A future project for an infrared telescope in space dedicated to asteroid-hunting.

Chapter 9: Outside the box thinking (my favorite chapter). 1. Painting an asteroid so that photons from the sun will push it into a different course. 2. Ion thruster. 3. Gravitational thruster. 4. Railguns. 5. PI Terminal Defense (rockets launched into space stop leave metallic rods in the path of an asteroid until the asteroid runs into them, shredding itself). 6. Vertical Gun.

Chapter 10: DART impact on Dimorphos

Chapter 11: DART successful. It changed the path of Dimorphos such that it's orbit was reduced by 32 minutes.

I read this book concurrently with Nemesis by Isaac Asimov which was an amazing choice and I found some fun parallels. In short, this is a cool read, especially if you are into reading about space.

[Popup-ch · Rating 4 out of 5]

The earth has been pummelled by asteroids and comets throughout its history, and the probability that it will happen again is almost 100%. Comets like the one that killed the dinosaurs are thankfully very rare, but impacts like the Tunguska event are projected to occur on average every couple of centuries. And Chelyabinsk-style events roughly every century.

What can we do to reduce this probability?

There are several ongoing projects to detect the potential impactors, as well as some attempts at deflection. The most explicit was DART (Double Asteroid Redirection Test), which was assembled and launched during the covid pandemic and was a complete success in 2022.

The penultimate chapter describes how the DART team celebrated the final collision and the demise of their cherished project. (Spoiler alert: It was a huge success.) The final chapter asks what to do next; we have shown that we can deflect impactors, if we see them far enough in advance.

There are projects to look for and trace Near Earth Objects - but they're not getting anywhere near the attention (or funding) required. For an eye-opener, look at cneos/sentry where thousands of objects are listed, with their probability of impact, and the energy that they could impart in case of an impact, ranging from 1e-4 to 1e6Mton - i.e. from a massive conventional explosion to order of magnitudes times Tsar Bomba. At the time of writing, the probability of an impact in 2032 is ~2%, which would result in a hiroshima-style explosion.

The book reads like a fast-paced documentary movie-script, with rapid cuts, jumping back and forth between separate story lines. It sometimes feels a bit contrived, but it mostly works.

[Patrick · Rating 5 out of 5]

Have you ever thought "Could an asteroid destroy the age of man the same way it did the age of the dinosaurs?", or pondered "How much science fact or fiction are in films like Armageddon, Deep Impact and Don't Look Up?", or maybe even wondered "If there is a space borne object with earths name on it is there something, anything, humanity can do to save itself?" If the answer to any of these is a yes, or you just have any interest in asteroids, NASA, engineering or space, then this book will definitely be right up your street.

As the latter part of this book title suggests, it deals with the real science of defending our home planet. While this book is firmly planted in science fact, much of this could easily be mistaken for science fiction, such is the nature of planetary defence. Its principal focus is on NASA's recent DART mission and, at times, turns into an unexpected page turner as you follow the trials and tribulations involved in man kinds first test of celestial self-defence. It also pulls in plenty of additional information, much of which is fascinating, intriguing and occasionally worrying.

Andrews writing style is flamboyant but thoughtful, giving what feels like real insight into not only the subject matter, but also a window into the lives and personalities of the people interviewed.

I thoroughly enjoyed reading this book cover to cover, and if you're reading this review then I can only assume you're considering reading this too. Do it, you won't be disappointed.

[Bob Schmitz · Rating 4 out of 5]

A selection for the OLLI science book club. The cover makes it look silly, but it was actually very interesting.

NEO, near Earth objects, as of June 2023 astronomers had found over 23,000 NEO’s, 850 which are of the 3000 foot and above planet killer variety.

DART: double asteroid redirection test. It’s a bacronym.

It seems that most of the scientist, astrophysicist, described in this book or women.

What this team did was send up a rocket to intercept an asteroid millions of miles away, traveling almost a year and then smashing it into it and redirecting it just a little bit to change its flight!!! Really unbelievable.

Asteroids are primarily made of rock and metal, while comets are composed of ice, dust, and some rocky material.

Now, I should add that I found the book fascinating but hard to follow with the difference between asteroids and comets and meteorites. Maybe I’m just not smart enough to read a book like this, but it seemed to me it could be more clearly written for us lay people.

Misc:

Boffin: British slang for a scientist.
Comets: from Greek KOMETES, which means hairy one
Rocks in space: asteroids, rocks on ground: meteorites, asteroids entering the earths skies: meteors.
Eschatological: concerning death
Coruscating : sparkling.
Saudale: nostalgia, longing, from Portuguese.
Empyreal: related to the heavens
Simulacrum: an unsatisfactory imitation of something else
Diamantine tears? Like diamonds.
Sibilating: hissing

[Catherine Puma · Rating 5 out of 5]

I'm thrilled that I won the Goodreads giveaway and read this soon after receiving it in the mail! I submitted to the giveaway because I'm really interested in this topic, and this definitely delivers on its extensive research. While the core narrative arc focuses on the DART mission, Robin George Andrews also gives due attention to Hayabusa2, OSIRIS-Rex, and Arecibo Observatory.

Andrews has a good sense of balance between his anecdotes, interviews with scientists on these missions, and research. He manages the tension so well that this popular nonfiction flows like a science thriller. I'm usually a slower reader, but I couldn't put this down, finishing it only in a few days!

In all honesty, I am not a fan of the book cover. It's busy and juvenile, so if I hadn't won the giveaway, I might not have sprung my purse to get it myself. But please don't let this stop you if you're interested! Read a few pages before making a decision. If the exciting planetary defense topic doesn't lock you in, Andrews' endearing humor will.

[Scott Martin · Rating 3 out of 5]

(3.5 stars) A solid overview of how NASA and other related organizations work to provide a way for humanity to thwart the existential threat that might be a meteorite strike. This work covers the history of asteroids/meteors/meteorites that have hit the Earth, as well as the scientists working to find ways to prevent something akin to the extinction of the dinosaurs. They cover the DART program, which demonstrated that a small probe/satellite can disrupt the path of an asteroid before it could contact the Earth. The writing is a bit conversational, which is not a bad thing when a work like this could get way deep into the weeds on technical terminology. A readable work, but not the greatest thing ever written on the subject. Worth a library checkout.

[Stephanie · Rating 5 out of 5]

I loved this book. It's informative and interesting while also being exciting and funny. Andrews tells a thrilling first-hand account of NASA's DART mission, having been at mission control on impact day, and at times it reads like an Ocean's 11 of planetary defence. It also gives a fascinating overview of when and how asteroids have impacted our planet in the past (bye bye dinosaurs) and what the movies got right (or, er, wrong). If you love science and space, I really recommend this book. But you don't have to be a serious science aficionado to enjoy this book. It's brilliantly written and is a real page-turner. I devoured it in no time at all.

[Gendou · Rating 2 out of 5]

This book is pretty much trash. It falls into many of the worst popular science pitfalls. Much technical terminology is dumbed down using imprecise substitution words. The author writes using a lot of flowery language (and that's putting it kindly) meant to be engaging, but it just sounds to my ear like an old man trying to be hip with the kids. There isn't enough meat on the bones, either. This book doesn't contain anything you couldn't get browsing Wikipedia for a couple hours. Anyone who's been paying attention to space news for the past decade or two already will not likely learn any new facts reading this book.

[Helmling · Rating 5 out of 5]

Andrews profiles the DART mission--NASA's attempt to deflect an asteroid as a proof-of-concept for future deflection of dangerous space bodies--with wit and warmth. The cast of dedicated scientists and engineers come across as curious, quirky, and dedicated as they try to lay the groundwork for a future wherein humankind can reach out and swat away any space rock that threatens our terrestrial home. For all its sci-fi trappings, the story of planetary defense told here is rich with all the best aspects of humanity.

Just a delightful book.

[Michael · Rating 4 out of 5]

Robin George Andrews’ “How to Kill an Asteroid” is a delight. What? A book about asteroids with the potential to wreak serious havoc on Earth? Yep, that, and in Andrews’ hands, the serious subject matter is easy to understand. There’s enough of that British wit or snark that makes for a charming read. The threat he outlines through interviews and insights from experts is made a bit less terrifying by what those experts do. A+ dust jacket too. This is a terrific read.

[Keith Good · Rating 4 out of 5]

How to Kill an Asteroid is a delightfully geeky deep dive into the NASA’s DART Mission, a proof-of-concept asteroid killer should Earth be threatened. The writing is playful and thorough, unafraid of Legend of Zelda and Star Wars references, with an almost tense countdown as the spacecraft closes in on destiny. It’s rare for a modern science book to be so entertaining and uplifting; How to Kill an Asteroid, appropriately enough, smashes it.

[Emily Browne · Rating 2 out of 5]

I really enjoyed this book in principle, the writing style suits it well and the content was very understandable and thorough. Holy crap though, can we please have some usable units? Fine, include the weird imperial ones but at least put the units most humans use in brackets following them. Really made it hard to understand scale, which this book quite crucially describes a lot. Genuinely made it quite a frustrating read in the end, which was a real shame.

[Robin · Rating 5 out of 5]

I might be a little bit biased, but if you want some stellar narrative non-fiction -- the absurd, true story about a group of scientists and engineers literally trying to save the world from killer asteroids -- then this is definitely worth your time. Cinematic, and surprisingly funny, it'll put a huge grin on your face.

[LeastTorque · Rating 4 out of 5]

Comprehensive and excellent coverage of the DART mission and overall state of asteroid detection and deflection science. Sometimes a little too comprehensive about the personal side. Some of that is welcome, to make the players real and help boost science as a career.

I had previously read the author’s book on volcanoes, so I expected this one to be good and it was.

[Charlie · Rating 3 out of 5]

An interesting book about what the world would really do if an asteroid was immanently out to get us. I think it could have been a third shorter and still got the same information across, but it was well worth the read. It seems we still have quite a way to go to actually be capable of doing anything very much, including detecting it in time, but the USA at least are doing work to correct that.

[Rebecca · Rating 3 out of 5]

The science of space and asteroids was well written, easy to understand and follow.
Found the venture into the politics of COVID unnecessary as there were different and various opinions and positions within the scientific community itself which were not presented.

[Alfredo · Rating 5 out of 5]

From the origins of the planetary defense movement to watching NASA’s historic DART mission succeed from mission control, How to Kill an Asteroid is a wild, but hopeful, ride on how humanity has the ability to not end up like the dinosaurs!

[Lisa · Rating 4 out of 5]

I enjoyed this book about the potential of asteroids crashing into earth and how scientists are actively researching and experimenting ways to stop catastrophic strikes to the earth’s surface. Interesting read. Thanks to the author/publisher for this Goodreads giveaway. It was a fascinating read.

[Edward ott · Rating 5 out of 5]

An extremely well researched and insightful book. We are doomed.

[Brooks · Rating 4 out of 5]

Good quick read!!

[Tanner Goldberg · Rating 4 out of 5]

Thank god someone is trying to deflect asteroids away from the earth, because I've been putting a lot of energy into the rituals I do to summon asteroids to strike the earth.

[Nicholas Smith · Rating 1 out of 5]

Tedious at all times. Could have been 1/2 the length and been just as informative.